1. Field of the Invention
The present invention relates to a camera having an in-exposure zooming mechanism for driving a zooming lens during exposure of a film.
2. Description of the Related Art
Conventionally, in order to obtain a special photographing effect, an in-exposure zooming photographing operation for performing a zooming operation during exposure of a film using a camera attached with a zooming lens is known. However, since a zooming operation during exposure requires a skill, it is a high-level photographing technique for general photographers.
Published Unexamined Japanese Patent Application No. 61-228426 discloses a technique for zooming a zooming lens by an electric motor to perform an in-exposure zooming photographing operation.
Published Unexamined Japanese Patent Application No. 63-318531 discloses the following technique. That is, when an in-exposure zooming photographing operation is performed in a state wherein a principal object is present with a dark background, a zooming operation is started after the background image is exposed for a predetermined period of time, and the magnification of the principal object is fixed at an emission timing of a flash device, thereby attaining proper exposure.
When a zooming operation is performed after exposure is performed for a predetermined period of time by combining the in-exposure zooming operation and a flash photographing operation, an emission timing of a flash device is preferably closer to the end of exposure as much as possible. When the principal object is a person, he or she may mistake the flash emission timing as the end of a photographing operation, and may move although exposure is still being executed, resulting in an undesired photograph.
A rear-curtain synchro photographing operation described in Published Unexamined Japanese Patent Application No. 63-318531 described above is effective in solving this problem. However, the following problem is left unsolved.
That is, a principal object image cannot have a desired magnification depending on a zooming start timing, and a flash emission timing. More specifically, according to Published Unexamined Japanese Patent Application No. 63-318531 described above, when the rear-curtain synchro photographing operation is combined with the in-exposure zooming operation, since a flash device emits light during a zooming operation, the magnification is unknown until a corresponding photograph is developed.
When a zooming lens causes movement of a focal point during zooming, the principal object image is photographed in an out-of-focus state. More specifically, a zooming operation is started in an in-focus state for the principal object, and when the flash device emits light during zooming, a principal object image is photographed by the light emission in an out-of-focus state since the focal point of the lens is moved during zooming.